Chimneys and flue pipes are widely used for furnaces, stoves and fireplace installations in order to vent off the products of combustion along with waste heat. Needless to say, great amounts of heat are discharged via the usual chimney and conventional flue pipes, usually as a necessary adjunct to convectin flow for draw. That is, the furnace or stove appliance must have a through flow that will ensure the removal of smoke and its discharge up the chimney or flue. For example, a free standing fireplace or the like is usually joined by a single walled connector flue pipe to chimney sections, while flue pipe that is double or triple walled extends through the building structure and roof in order to isolate heat from the surrounding combustible construction. This chimney or flue pipe is used quite extensively to extend between floors and through attics, and it is this type of heat isolating pipe which is used advantageously herein to replace the ordinary single walled connector pipe and to conserve heat as it travels from the appliance to the ventilator of the present invention. In other words, double walled flue pipe is employed herein to cooperate between the appliance and ventilator. And with the present invention, double walled flue pipe opens to receive useful air at the appliance, and serves to confine the heat of flue gases to the flue tube therethrough while maintaining a relatively cool exterior and ventilator housing.
Heating ventilators for retrieving waste heat have been provided in many forms, characterized by baffles and circuitous routing of either or both the flue gases and useful air to be heated and discharged into a living area. In some instances the flue gases have a straight through flow, and in others a restrictive route that exposes the same to heat transfer elements, and in some instances it is the useful air that is restrictively diverted, or both as stated. It is a general object of this invention to restrict neither body of moving gases and air, and to provide a heat transfer unit having the least impedance to flow in each instance. Highly important is the free flow of flue gases which rely upon convection for the discharge of smoke, and with the present invention the flue gases are transported longitudinally through a straight unobstructed tube with smooth walls. Also highly important is the low pressure high volume delivery of heated useful air in an unobtrusive quiet manner, and with the present invention the heated useful air is transported transversely through a housing comprised of a plurality of straight unobstructed plates with smooth walls.
The unobtrusive delivery of useful air at low pressure and high volume is an object of this invention, and to this end a motor driven fan operates in a plenum and on a transverse axis to transport the useful air to be heated by the aforesaid plates. The plenum opens downwardly to receive the rising convection flow of useful air from the heated area surrounding the appliance, such as a free standing fireplace or the like, and the aforesaid housing is louvered so as to direct the discharge of heated useful air downwardly.